EXPERIENCE WITH MgO-BEARING MATERIALS FOR RAISING
THE STABILITY OF CONVERTER LININGS
A. V. Kushnarev,
E. A. Visloguzova,
A. S. Ustenko,
and S. A. Remigo
Translated from Novye Ogneupory,No.4,pp.3–5,March, 2007.
Original article submitted January 30, 2007.
Accumulated experience shows that one can increase the resistance of converter linings in various ways, with
the largest effect from the use of self-decomposing magnesium materials in the form of granules or briquettes.
The advantage of these materials comes from the presence of hydrated or carbonate components producing
explosive decomposition on entry into the converter slag, with the slag rapidly saturated in MgO, with an in
crease in viscosity and the formation of a stable lining.
One can deposit a specially prepared slag on the lining of
an oxygen converter, which throughout world ferrous metal-
lurgy is used to increase the resistance of the lining and thus
reduce the consumption of replaceable refractories and the
costs of repairing linings and plant. The converter lining re-
sistance is increased by a substantial factor and has attained a
maximum of 15000 cycles in China with a mean level of
6000 – 10000 cycles and an absolute record in Canada of
30000 cycles. In attaining such resistance, great importance
attaches to the slag formation technology, i.e., the production
of a slag for coating the lining, in connection with which the
slag needs to be modified. The modifiers are specially added
materials whose production is based on various MgO-bear
The special slag for coating the lining should have cer
1) it should be adequately refractory, i.e., its melting
point should be above that of steel;
2) it should adhere well to the lining;
3) it should have high thermal, slag, and metal resis
4) it should be viscous and at the same time reasonably
light, which is attained by gas saturation.
The refractory coating should have physicochemical and
other properties to provide a balance between erosion and
protection of the lining. Certain conditions are also required
for applying the refractory coating:
1) the slag should have the best MgO content;
2) the oxidation of the slag should be optimized;
3) the slag temperature should be reduced to the liquidus
level (or the liquidus level should be raised to the actual tem-
4) a special design of deposition equipment is required to
emplace the slag [1, 2].
Before slag deposition was introduced at this corpora-
tion, the MgO contents of the slag usually were 5 – 7%. Then
when the MgO content was less than 7%, large amounts of
the phase nCaO × Fe
were formed with melting point be-
low 1440°C, so the erosion resistance of the projective layer
was poor . To make the slag coating more refractory, the
MgO content has been raised to ³ 10%, i.e., it has been
raised by reducing the CaO content and increasing the MgO.
In that case one produces 3CaO × SiO
and 2CaO × SiO
their high melting points (2070 and 2130°C respectively).
In the MgO–FeO and MgO–Fe
systems there are continu
ous solid-solution series of magnesiowüstites and magnesio
ferrites, which also have a high melting point (1713°C) .
The absence of free calcium oxide in the slag liquid is a nec
essary condition for the formation of a viscous high-tempera
ture slag. Although the contents of iron oxides in free form
adversely affect the lining, if there are only small amounts of
them, one does not get complete dissolution of the MgO to
content in the slag of 8 – 10%. If for example the FeO con
tent in the slag is 20 – 25%, only half of the MgO is taken up,
while the other half remains in solid form and increases the
heterogeneity and refractoriness of the slag . However,
when a mild steel is melted, the elevated FeO content in tem
peratures above 1670°C cause such slags to be flushed away.
In that case one needs additional increases in the concentra
Refractories and Industrial Ceramics Vol. 48, No. 1, 2007
1083-4877/07/4801-0009 © 2007 Springer Science+Business Media, Inc.
Nizhny Tagil’ Metallurgical Corporation Ltd., Russia.